B5 Passat TDI

[JFettig]

Its an AHU/1Z/AFN/AHH style valve cover, not AAZ

Road tube? whats road tube?

Currently only running 30psi, ***s acting goofy for some reason. I don't think my ECU likes to control anything over 26psi. I ran 32psi for a couple test tunes and that's the end goal
I might drop the boost down a little more because winter tires  + 30psi = wheel spin until like 50mph.

[CrazyAndy]

Road tube is running your PCV hose to atmosphere, around the bottom of the car.  Old cars used to do it until the 60s, when they had to run them into the air cleaner for emissions and cleanliness.

Sounds like you're due for a ECM reflash when the weather gets warmer.  Probably cuts the MIL on and gives the P0234 code.  25 psi seems to be the limit for stock/light VAG-COM ECM fuel mapping.  Or does it do stuff weirder than that?

And yeah, forgot the early TDIs ran 3-nut VCs.  Just shows how many come into the dealership anymore.

[JFettig]

Some call it an elephant hose too.
I run it inches from my downpipe to keep it nice and warm in the cold climate.

No P0234 code, its a glow plug code. My ECU is full re-mapped already, done a few tune updates lately. I am running a 4bar map

Its a boost oscillation, normally when the vanes are relaxed to prevent an overboost situation the boost levels out nicely, this turbo seems too anxious and the boost drops rapidly, then it overcorrects, and so on.